Sieve-centrifuge



'w. HIRSCH Sept. 27, 1966 SIEVE-CENTRIFUGE Filed Oct. 1'7. 1965 INVENTOR. W. H 6 rs c h 6hatu l %exm TTO ILNEES United States Patent 3,275,153 SIEVE-CENTRIFUGE Wolfram Hirsch, Monheim, Rhineland, Germany, assignor to Hein, Lehmann & Co. A.G., Dusseldorf, Germany, a firm of Germany Filed Oct. 17, 1963, Ser. No. 316,930 4 Claims. (Cl. 210-369) This invention relates to a sieve-centrifuge and refers more particularly to a continuously operating sievecentrifuge for the separation of mixtures of solids and liquids, which is particularly suitable for viscous sugar masses.

The invention is concerned with a centrifuge of the type having a conical sieve drum the surfaces of which extend outwardly upwardly, the mixture to be separated being supplied through an accelerator pot located at the lower end of the drum coaxially therewith and rotating in the same direction as the drum, the non-perforated wall of the pot having a lesser angle of taper relatively to the drum axis than that of the drum.

Prior art centrifuges of this type are provided with a non-perforated accelerator pot located at the lower end of the drum and having smooth inner surfaces. The height of the pot must not be below a certain minimum, so as to enable it to eject with sufiicient acceleration the mixture to be separated which is supplied into the middle thereof; the ejected mass must be guided carefully and with suflicient rotary speed corresponding to the rotary speed of the drum to the lower end of the conical perforated drum. Therefore, the inclined side walls of the accelerator pot must be made of such height that sufficient acceleration is imparted to the mixture flowing out of the pot, so as to enable the drum to take over the mixture. This also requires that the centrifugal drum be constructed of not less than a certain minimum height. The drawback of a drum of this height is not only that it occupies a great deal of space, but that its stability is detrimentally affected, since there is a comparatively large distance between the sieve drum rotating with high speed and its pivot bearings located usually below the accelerator pot; thus tilting moments and unbalancing torques can appear which will have a detrimental action upon the drum supports.

An object of the present invention is to eliminate the above mentioned drawbacks and to improve the construction of the centrifuge of the described type.

Another object is the provision of a continuously operating sieve-centrifuge, particularly suitable for viscous sugar masses, the height of the drum of which can be considerably reduced, while retaining a good acceleration effect of the accelerator pot upon the mixture to be separated.

Other objects of the present invention will become apparent in the course of the following specification.

In accomplishing the objects of the present invention it was found desirable to provide the accelerator pot with an inner surface which is totally or partly roughened, punched or corrugated, or provided with waves or ribs, so as to increase the sliding resistance to the mixture moving over the surface. The waves, ribs or the like provided upon the inner surfaces of the pot extend preferably concentrically to the drum axis.

This feature of the present invention makes it possible to construct the accelerator pot, i.e. its conical side wall, considerably shorter than in prior art constructions, with out diminishing the impetus effect of the accelerator pot upon the mixture to be separated, which passes over it. Particles of the mass or filling which become partly embedded in the depressions provided in the pot, form a blunt surface which exerts a correspondingly increased entraining effect upon the mixture which passes over them,

Patented Sept. 27, 1 966 so that despite the shorter acceleration path in the accelerator pot an adequate acceleration of the mixture is achieved with reference to the speed of rotation of the sieve drum.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawing showing, by way of example, preferred embodiments of the inventive idea.

In the drawings:

FIGURE 1 is a vertical section through a centrifuge for sugar masses provided with a sieve drum and an accelerator pot constructed in accordance with the present invention.

FIGURE 2 is a section through the accelerator pot on an enlarged scale.

FIGURE 3 is a partial sectional view illustrating an accelerator pot having a different inner surface.

FIGURE 4 is a partial sectional view illustrating another accelerator pot with a different inner surface.

The centrifuge drum intended for sugar masses and shown in FIG. 1 includes a frusto-conical upwardly outwardly extending sieve drum 1 of the type known in prior art, and an accelerator pot 2 located at the lower narrower end of the drum. Sugar masses which are to be centrifuged are supplied to the center of the pot 2 through a charging pipe 3.

The centrifuge drum is driven by a suitably mounted drum shaft 4 to which quick rotation is imparted by a drive motor not shown in the drawing.

In operation, the mixture supplied to the middle of the pot 2 by the pipe 3 is accelerated by the rotating pot to such an extent that by the time it reaches the lower end of the sieve drum 1 it has already a speed of rotation corresponding to that of the drum. This assures that the mixture is guided to the sieve surface with adequate safety. Liquid separated from the mixture is ejected through the perforations of the sieve drum lining 1' and the openings 1" of the drum body 1" carrying the lining; the liquid flows into a collecting chamber for the liquid (not shown) which concentrically encloses the drum. On the other hand, the solid sugar particles travel upwardly over the drum lining, then move outwardly over the edge 1"" of the sieve drum and are ejected into a collecting chamber for solids (not shown) which annularly encloses the collecting chamber for the liquid.

As already stated, in prior art centrifuge drums the accelerator pot located at the lower end of the drum had smooth flat inner walls.

On the other hand, in accordance with the present invention the inner surfaces 5 of the pot 2 are completely or at least partly roughened, punched or corrugated, or provided with waves or ribs, so as to increase the sliding resistance of the mixture being centrifuged which travels upwardly over the inner surfaces 5.

FIGURES 2, 3 and 4 show pots 2, 2' and 2 provided with somewhat differently shaped inner surfaces 5, 5' and 5", respectively. a

The common feature of all these constructions is that the ribs 6 (FIG. 2) located upon the inner surfaces extend concentrically to the axis of the drum. This has the effect that while the accelerator pot is rotated, the mixture moving upon its inner surface 5 will be subjected to an increased frictional or entraining action. Due to this effect, the height h of the accelerator pot of the present invention may be made considerably smaller than the height of prior art pots. Despite this shortened acceleration surface availa ble for the mixture, it will be nevertheless accelerated by the pot of the present invention to such an extent that the mixture reaches the lower edge of the sieve drum 1 with a rotary speed corresponding to the speed of rotation of the perforated sieve drum.

In the construction shown in FIG. 2 the inner surfaces. of the pot 2 are provided with ribs 6 having fiat outwardly directed surfaces .6, while grooves 7 are located between the ribs 6.

In the construction shown inFIG. 3 the inner surfaces 5 of the pot 2 are provided with .pointed ribs and grooveswhich are angular in crosssection.

In the construction shown in FIG. 4 the inner surfaces 5" of the pot 2" have rounded ribs and grooves of wavy outlines.

It is apparent that the examples shown above have been given solely .by way of illustration and not 'by way of limitation and that they are subject to many variations and modifications within the scope of the present invention. All such variations and modifications are to be included within the scope of the present invention- What is claimed is: V

1. A sieve-centrifuge, particularly for viscous sugar masses, comprising in combination with a rotary frustoconical sieve drum having a narrower lower end and meansv directed toward said lower end for supplying the 20 2. A sieve-centrifuge :in accordance with claim 1, wherein said ribs have flat outer surfaces.

3. A sieve-centrifuge in accordance. with claim 1, wherein said ribs and grooves are angular in cross-section.

4. A sieve-centrifuge in accordance with claim' 1, wherein said ribs and grooves are wave-like in cross-section.

References Cited by the Examine:

UNITED STATES PATENTS Re. 20,829 8/1938 Roberts 210380 1,259,048 3/1918 Roberts et al. 210380 1,669,235 5/1928 Fenton 210380 X 1,903,298 4/1933 Roberts 210-38O X 2,973,288 2/1961 Riedel' 210-380 X 3,108,067 10/1963 Dietzel eta 2l0380 

1. A SIEVE-CENTRIFUGE, PARTICULARLY FOR VISCOUS SUGAR MASSES, COMPRISING IN COMBINATION WITH A ROTARY FRUSTOCONICAL SIEVE DRUM HAVING A NARROWER LOWER END AND MEANS DIRECTED TOWARD SAID LOWER END FOR SUPPLYING THE MEANS TO BE CENTRIFUGED; AN ACCELERATOR POT LOCATED AT SAID LOWER END AND ROTATING ALONG WITH THE DRUM, THE INNER SIDE AND BOTTOM SURFACES OF SAID ACCELERATOR POT BEING ROUGHENED AND NON-PERFORATED AND CONSISTING OF RIBS EXTENDING CONCENTRICALLY TO THE AXIS OF THE DRUM AND GROOVES BETWEEN SAID RIBS TO IMPART INCREASED FRICTIONAL AND ENTRAINING ACTION TO MASSES MOVING UPON SAID INNER AND BOTTOM SURFACES. 